I downloaded and installed version 2.3 build 3, running under WinXP. I must say, it's extremely buggy and I'm very disappointed -- and unlikely to pay for it, to be perfectly honest. Crates and even bits of wall simply disappear for no discernable reason. The game stops and refuses to respond for 5-6 seconds at a time at irregular but frequent intervals. The pusher moves too slowly for my taste and there's no way to speed him up that I can find.
Are these known issues? I looked through this Bugs forum and didn't see any mention of them.